With rapid development of mobile communications technologies, demand for mobile service traffic becomes larger. To satisfy the fast-growing demand for service traffic, data offloading may be performed on a macro cellular network, and small cells are densely deployed in some indoor or outdoor hot spots. The small cells herein may include: a metro cell, a micro cell, a pico cell, a femto cell, a wireless local area network (WLAN) using a Wireless Fidelity (Wi-Fi) technology, and the like. These small cells have features of small coverage and low transmit power, and are applicable for high-speed data transmission services.
Due to small coverage of a small cell, a service volume of user equipment (UE) served by the small cell often changes. If UE currently within a small cell does not need to perform service data transmission, the small cell may be temporarily disabled to save energy, and in this case, the small cell stops sending signals. When the UE within the small cell needs to perform service data transmission, the small cell may be enabled, to provide a data transmission service for the UE. When the UE served by the small cell does not need to perform service data transmission, disabling the small cell not only can save energy for the small cell, but also can reduce signal interference from the small cell to another cell and improve a channel environment of a communications system, especially in a scenario in which small cells are densely deployed.
However, when the small cell is disabled, the UE considers by default that the small cell always sends at least cell-specific reference signals (CRS). Therefore, the UE performs measurement and/or synchronization by using a CRS received in each downlink subframe. In this case, a result of the measurement and/or synchronization performed by the UE is obviously erroneous.